Biodegradation and Properties of Phosphated Polyurethanes
Siddique, Nehnah
Siddique, Nehnah
Publication Date
End of Embargo
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The University of Bradford theses are licenced under a Creative Commons Licence.
Peer-Reviewed
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Accepted for publication
Institution
University of Bradford
Department
School of Chemistry and Biosciences. Faculty of Life Science
Awarded
2023
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Abstract
Vast quantities of plastics are produced annually, to meet the expanding global demand. The use and misuse of plastic, followed by the subsequent mismanagement of waste, has raised great environmental concerns. Despite the recognition of the problems faced the production of plastic continues to increase. This along with the resistance of most polymers to degradation highlights the requirement of further investigation into effective methods of biodegradation, as well as into the synthesis of biodegradable polymers.
Three standard polyurethanes with varying soft:hard segment ratios were synthesised and characterized via FTIR, 1H NMR and GPC. Phosphate-functionalised polyurethanes (GP-PU) with equivalent soft:hard segment ratios were also synthesised and characterised. The degradation properties of each PU and GP-PU were studied and compared, under various controlled conditions. Bacteria and fungi contributing towards the degradation of these material, were also identified, via DNA sequencing of the 16S and ITS1 rRNA regions, respectively.
The thermal and mechanical properties of PUs and their equivalent GP-PUs were also studied and compared, at each composition to determine how the addition of phosphate affected the materials final properties. Various techniques were used including, thermogravimetric analysis, differential scanning calorimetry and tensile testing. It was demonstrated how the incorporation of phosphate functional groups to polyurethanes resulted in materials with enhanced thermal and mechanical properties.
In this thesis it is demonstrated how the addition of phosphate to polyurethane, results in materials which are significantly more amenable to biodegradation whilst also enhancing their mechanical properties, when compared to their non-phosphated equivalents. Species of both bacteria and fungi were found to be greatly amplified on the film surfaces, contributing towards this enhanced biodegradation.
From 16S analysis, the two predominant species of bacteria on the film surfaces were Melioribacter roseus and Ignavibacterium album. From ITS1 analysis, the two species of fungi amplified on the film surfaces were Talaromyces rugulosus and Saccharomyces cerevisiae.
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Type
Thesis
Qualification name
PhD